Process for treating complex sulfid ores.



GEORGE'E. KINGSLEY, or SPOKANE, WASHINGTON.

PROCESS FOR TREATING COMPLEX SULFID ORES.

No Drawing.

To all whom it may concern: 7

Be it known that I, GEORGE E. KINosLEY, a citizen of the United States, residing at the city of Spokane, in the county of Spokane and State of lVashington, have invented a certain new and useful Improved Process for Treating Complex Sulfid Ores, of which the following is a specification.

My invention relates to an improved process for treating complex sulfid ores, such as ores containing galena, zinc, pyrites, etc. It is also applicable to v lead ores which do not carry sulfids.

The obj ect'of my invention is to avoid the 3 the following metals, antimony, copper, bismuth, etc., on account of the formation of sulfates of the different metals, which are insoluble, and which will always be formed J if the strength of the acid used is greater than five per cent. By the use of five per cent. or less of acid, the formation of sulfates is entirely prevented, nitrates being formed instead, and consequently complete extraction can be effected, the metals being recovered from solutions of nitrates.

' It is essential in the operation of my process that the solution be heated to one hundred and seventy-six degrees Fahr. in order that the oxids of nitrogen be liberated and free sulfur deposited. The variation of the degree of heat must be very slight indeed, and I find in practice that the variation of more than one-half degree will afi'ect deleteriously the action of the dilute nitric acid.

To avoid a large-volume of a dilute solution containing a small percentage of metal- Speciflcation 0t Letters Patent.

Patented June 29, 11915.

Application filed January 22, 1915. Serial No. 3,801.

lic contents, when the acid present has used up its energy and the solution is still at the desired temperature five per cent. more acid is added, and so continued until a saturated solution is obtained. The solution is then drawn oil" and a fresh solution added until the metallic contents present is entirely dissolved and free sulfur deposited. By so doing, a great saving is effected in time, fuel and labor. Any convenient form of closed solution tank may be employed, and if desired means can be provided for agitation. After the metals have been dissolved by the nitric acid they can be removed from the solution by well known means.

The oxids of nitrogen can be reconverted to nitric acid by well known means. The solutions of nitric acid can then be treated for the recovery of lead contents by precipitating the lead in the form of a high grade pigment. Lead also may be recovered in the metallic form by Well known means.

Other metals, such as zinc, iron, copper, and silver, if present in the ore, will be dissolved with the lead and can be separated and recovered by well known means of precipitation.

In practice, I have found that the strength of. the solution of nitric acid, as well as the degree of heat, are essential; so much so, indeed, that unless practically the exact strength of acid and degree of heat are followed in carrying out my process, the

result which I desire to obtain cannot "be efiected, and I, therefore, lay emphasis on this fact.

What I claimas my invention is- In the treatment of complex sulfid ores, the process of immersing the ores in a dilute solution of nitric acid of a strength of five per cent. or less, and heated to one hundred and seventy-six degrees Fahr., whereby a nitrate is produced and sulfur in its natural state, as and for the purpose specified.

GEORGE E. KINGSLEY.

Witnesses:

G. J. BOWMAN, HOMER G. KINGSLEY. 

